Our microfluidic Multiplex Immunodiagnostic Tumor Technology (MITT), which is able to sort blood components and catch a multitude of analytes, will be used to assess early host changes due to presence of a cancer. The ability to quantify a wide range of constituents from multiple organ systems as well as the cancer, itself, with high sensitivity and specificity will provide a holistic approach to evaluation of the physiological profile of cancer development. We predict that this instrumentation will be a substantial new technology for rapid early diagnosis of circulating tumor cells (CTCs) and of the host response induced by breast cancer. This device will be able to simultaneously quantify soluble analytes in plasma, blood leukocyte subsets and their released products, and CTCs, the critical and key parameter for this proposal. The fabricated chip at the heart of the instrument is able to fractionate blood into plasma, RBC/platelets, leukocytes, and CTCs with use of a micro-pillared array (plasma:cell sorter chip, PCSC) that precedes a grating-coupled surface plasmon resonance (GCSPR) chip capable of GCSPR or GCSP-enhanced fluorescence (GCSPEF) imaging; GCSPEF increases sensitivity approximately two logs, but requires secondary antibodies. The plasma constituents are captured on regions of interest (ROIs) with select antibodies. The plasma constituents will be screened for the host's immune and neuroendocrine response and stress-related proteins as well as tumor-specific antigens. Aim 1 will validate GCSPR/GCSPEF analysis with Luminex analysis and cell quantification by PCSC with flow cytometry. Aim 2 will determine the efficiency by which this technology can detect cancer and unique host biomarker profiles defining health status prior to detection of any palpable tumor. Cancer stage will be assessed by histology after blood assessments; female MMTV-PyMT mice with rapid onset of cancer will be compared to males and MMTV-neu mice as well as FVB controls used to obtain baseline values for blood biomarkers. Captured cells can be further phenotyped for released products or intracellular constituents after lysis. The technology will be optimized for sorting and capturing analytes for the greatest diagnostic and prognostic potential. The quantified profiles will delineate unique biosignatures that determine the characteristics of the host:cancer interaction. This technology will be useful for early cancer diagnosis, and we foresee using the technology to monitor tumor cell dissemination after surgery, tumor reoccurrence, and longitudinal therapeutic interventions.